In vitro studies into the use of denture base and soft liner materials as carriers for drugs in the mouth.

The potential of plasticized and polymerized acrylics to carry and release medicaments was investigated. Chlorhexidine acetate was incorporated at concentrations of 2, 5 and 10% into the powder phase of heat and cold cured acrylics and an acrylic gel soft liner. A preliminary bioassay demonstrated comparable release at anti-bacterial levels from all three materials. Spectrophotometric and agar diffusion measurements of the chlorhexidine released into water showed the duration increased with the concentration of chlorhexidine incorporated. At 10% admixture the release from the polymerized and plasticized acrylics was in excess of 100 days. Light and scanning electron microscopy of polished and fractured surfaces of the polymerized acrylic showed the chlorhexidine distributed throughout the matrix of the materials. Following soaking in water, holes appeared in the matrix, particularly in the surface zones. Sections of the acrylic gel soft liner demonstrated chlorhexidine distributed as particulate material. Soaking in water caused vacuolation of the material and at higher concentrations material break-up was apparent.